-39.5% is the change from 643 to 389
Calculation steps:
[( 389 - 643 ) ÷ 643] x 100 = -39.5%
Formula
Percentage change = [(389 - 643) / 643] x 100
Subtract the new number by the original number
389 - 643 = -254
-254 ÷ 643 = -0.39502332814930013
-0.39502332814930013 x 100 = -39.5%